Mix together the marinade ingredients olive oil, soy sauce, Worcestershire sauce, lime juice, garlic, salt and pepper to a large dish or to a large Ziplock bag. Add the steak and coat thoroughly with the marinade. Place in the refrigerator for at least 2 hours or up to 6. I do not recommend to marinade longer than 6 hours because the acid from the lime juice can break the meat down too much.
While the steak is marinating make the chimichurri sauce by chopping the parsley very finely, mincing the garlic and adding that to a bowl along with the olive oil, vinegar, red pepper flakes, salt and pepper. Stir and refrigerate for 2 hours for the flavors to mingle.
When ready to cook the steak, preheat an outdoor grill to 450℉-500℉. Clean the grill well and grease the grates by using a wadded up paper towel dipped in oil.
Place the steak on the hot grill (it's best to let the grill heat for 15 minutes before adding the steak). Cook for 4-5 minutes undisturbed and then flip and cook for an additional 4-5 minutes or until the internal temperature reaches 130-135℉ with a meat thermometer. This will be a medium rare steak which is recommended for this cut of meat. If you prefer your steak cooked to medium cook to 140℉ but do not cook past this point as it will result in a vary tough chewy steak. See temperature chart for guidance.
Once the steak is cooked to the optimal temperature, it is very important to allow the steak to rest for 5-10 minutes before slicing. This allows for the meat fibers to relax and the juices to reabsorb in the meat. If you cut too soon you will loose all the juice and have a dry steak.
When ready to cut it is very important that you cut the steak against the grain. When you look closely at the steak you can see the grain of the steak running in one direction. So cut in the opposite direction. It's that simple. The reason this is important is because it makes the steak much easier to chew and more tender. Cut in thin slices.
Once you have sliced the steak top with spoonfuls of chimichurri sauce and serve immediately.